Kiwamete Kenzen na Bishoujo level up [Volume 1] [Prologue] [Free]

The world gained dungeons. But the dungeons themselves only affected half of humanity.

Because only women could enter them.

Well, that wasn't entirely accurate. Men could physically enter them, but they didn't possess the concept of "levels." Defeating oncoming monsters, gaining EXP, leveling up, and getting stronger... that game-like reality only applied to women. Without leveling up, you couldn't get stronger. In other words, men were stuck at base stats.

Until a few years ago, sports like baseball and soccer were heavily male-dominated, but the appearance of dungeons flipped the script entirely. Men stood absolutely no chance against women who braved the dungeons and leveled up.

Instead of levels, however, a different concept manifested exclusively in men: "EXP."

Once a boy hit puberty, a numerical value would appear somewhere on his body. It could be a thousand, ten thousand, or even just one. That was his EXP. Of course, this wasn't some grim, violent setup where women had to kill men to harvest their stats.

"Both saline and sugar solutions cause water to move toward the higher concentration. This principle applies to other things as well..."

Far from violent, it was incredibly erotic.

The way a woman absorbed EXP from a man? Things like holding hands, kissing, or hugging. It required the kind of physical, intimate contact that lovers engage in.

"There are different types of semipermeable membranes. Take slugs, for example. You all know them. Their bodies are wrapped in a semipermeable membrane, so if you sprinkle salt on them, the moisture gets sucked right out. The same thing happens with sugar. And a similar phenomenon occurs in humans, too."

In dungeons, women had to risk their lives in battle to earn EXP. But they could also get it just by fooling around with a guy. Zero danger, it feels amazing, and you get a power boost. It was a total win-win.

"...And so, by plotting an exponential function graph, we can see that the amount of transferred EXP scales upward. Now, with that understanding, try calculating your own EXP capacity."

Naturally, the more EXP a guy possessed, the better. Having over ten thousand EXP made a guy incredibly popular. Men with over a hundred million were treated like super idols—honestly, they were practically at risk of getting assaulted. There was no way a guy could resist a woman who had leveled up in the dungeons and even acquired magic or skills. Rumor has it that men with over a trillion EXP were quickly taken into government protective custody to live out incredibly lavish, enviable lives.

"Everyone, plug in your own EXP values and figure out how much transfers based on each act... Hey, Mura Tatsuya, are you even listening?"

"Ouch!"

Before I knew it, Sensei was standing right next to me, smacking my head with a textbook. She looked down at me with sharp, narrow eyes, her ponytail swaying.

By the way, she hit me with her right hand—she didn't have a left one. Apparently, it got eaten by a monster back when she used to raid dungeons. She retired after that and became a teacher. That said, she was still a young, twenty-five-year-old instructor.

"Sensei, that's corporal punishment."

"Oh really? Want to try suing me then?"

Without caring about my complaint, she brought the textbook down on my head one more time before heading back to the podium. This wasn't chemistry class... it was health. Which meant the classroom was strictly boys only, except for Sensei.

Why on earth did a female teacher handle the boys' health class? Expecting us to pay serious attention was asking for the impossible. Especially since she was gorgeous and well-endowed. Her massive chest was trapped inside a tight shirt, looking like it could burst out at any second.

"In short, engaging in intense, intimate sexual acts involving mucous membrane contact transfers a massive amount of EXP to the woman. During this process, the woman experiences pleasure directly proportional to the influx of EXP. Now that you get it, Mura, don't be shy and do the math. This is important stuff."

Even if she called it important...

"Sagaranche-sensei! Mura doesn't have any EXP!"

Sakakibara, the friend sitting behind me, chimed in mockingly. Sagara Chie-sensei. Hence, Sagaranche-sensei.

"...Is that true?"

Men with absolutely zero EXP were virtually unheard of. Sensei cast a skeptical gaze my way. I rolled up my shirt sleeve and slid down the arm cover underneath. The character for "Null" peeked out on my right arm. Seeing it clearly even from a distance, Sensei's eyes widened in surprise.

"Oh... My bad. I guess people like you do exist. Well, whatever—EXP isn't everything for a man, so don't sweat it too much. Just make sure you pay attention to the lecture."

"Got it."

When I was a kid, the character for 【Null】 had manifested on my arm. Some of my friends had hundreds, thousands, or even tens of thousands. Yet, I had 【Null】. Ever since that secret got out, my guy friends teased me mercilessly, and the girls kept their distance.

By the way, while the guys were learning about how EXP worked, the girls were taking a class on dungeon raiding. Though apparently, "raiding" just meant getting a basic orientation on the first floor.

If I had been born a girl, would I be on a grand adventure with swords and magic like a light novel protagonist? As I mended these pointless thoughts, the chime rang to signal the end of class.

"You boys better burn this into your minds: you are the ones who get 'devoured.' Men cannot win against a woman who has leveled up. No matter how much you trust someone, never let your guard down. Alright, that's it for today. Mura, come to the nurse's office after school. Dismissed."

After watching Sensei walk out briskly, the classroom erupted into crude chatter. That's just how it goes after health class.

"Intense sexual acts with mucous membrane contact, she said!"

"Man, I'm already rock hard!"

"She said we're the ones getting devoured! I want to get devoured already!"

"Dude, your EXP is only three hundred. Nobody's devouring you."

Perverted talk is the universal language of high school boys. Even though the second year had just started and we'd barely formed this new class, everyone was already united, letting their vulgar conversations blossom. Listening to their voices, I turned my gaze out the window. The cherry blossoms outside were blooming beautifully, completely indifferent to the dirty talk echoing nearby.

"Excuse me..."

"You mean, 'Pardon the intrusion.' Whatever, take a seat."

When I entered the nurse's office after school, Sensei spoke without even looking at me. She seemed to be researching something on her computer. Staring at the screen and moving the mouse with her right hand, she nudged a nearby chair with her foot. Not the best manners, but I guess that's standard for a former dungeon diver.

"Are you going to scold me for not listening in class?"

"I do want to lecture you about that, but this is a separate matter."

Once I sat down, Sensei turned her body toward me and looked straight into my eyes.

"Mura. I didn't know you lacked EXP, and I said something insensitive. First, I want to apologize for that. I'm sorry."

Sensei bowed deeply. There weren't many teachers who would face a student so earnestly.

"You don't need to apologize. Everyone knows about it anyway, and I don't really mind."

"Even so. I'm sorry."

"...Alright. Thank you for being considerate."

When I answered, Sensei raised her head and offered a slight smile.

"So, having just apologized, it might seem bad to ask this immediately, but... could you show it to me one more time?"

"Sure, I don't mind."

Just like during class, I rolled up my sleeve and arm cover. The character 【Null】 was still right there. Sensei stared at it for a while before looking back at her computer.

"It really does say 【Null】. But it's strange. I used to be a dungeon diver, so I know a fair bit about EXP, but I've never seen or heard of the character for 【Null】 being used."

"Well, guys with no EXP are pretty rare to begin with."

"No, that's not what I mean. Look at this."

Sensei turned the computer screen toward me.

"Men with no EXP have the notation 【Zero】 or 【0】. The existence of a 【Null】 notation has never been confirmed. Not for anyone besides you."

"Huh. Well, I definitely have 【Null】."

"...Hey, Mura. Do you really have no EXP? Have you ever... tested it?"

"Sensei. Isn't that sexual harassment?"

"Ah! S-Sorry! I asked something inappropriate again..."

Asking if I'd tested it was basically asking if I'd ever been intimate with a woman.

"It's fine. Besides, whether it's 【Null】 or 【Zero】, it doesn't change the fact that I don't have EXP. Is that all? If so, I'll be taking off."

As I stood up, Sensei reached out to me in a panic.

"Mura, wait! Let me get a closer look at it one more time!"

"Ah, wait—!"

Before I could dodge, Sensei grabbed my arm.

"Oh crap! Let go!"

"Huh? ...Ah, ah, ah... Aaaaaahhhhhhh! ♡♡♡♡♡♡♡♡♡♡♡♡"

Hearts practically popped into Sensei's eyes as she leaned backward.

"Sensei! Let go of me!"

I frantically pulled back, but there was no way I could match the physical strength of a former dungeon diver. We tangled together and tumbled right onto the nurse's office bed. Sensei collapsed directly on top of me. Caught in an awkward, strained position, the buttons on her shirt burst right off.

"Wh—?!"

Before I knew it, my face was buried right between her voluptuous breasts. At the exact same moment, Sensei's entire body shuddered violently.

"Nnh... haaaaaaaahhh! ♡♡♡♡♡♡ M-Muraaaaaa! ♡♡♡♡♡♡ Res... EXP! ♡♡♡♡♡♡"

"S-Sensei?!"

"Oh, oh, oh, oh... ♡♡♡♡ N-Noooooo! ♡♡♡♡ S-Something like this... It's my first timeeeee! ♡♡♡♡♡♡"

"SENSEIIIIIIII!"

Her screaming voice was surprisingly cute.

"Man, I really messed up... I was trying to be so careful..."

After that, Sensei had rolled her eyes back and fainted with a face that definitely shouldn't be shown to the public. I laid her on the bed and practically fled back to the apartment where I lived alone.

I heated up some frozen dan dan noodles, ate quickly, and headed to the bathroom. After washing up, I soaked in the tub and rubbed my right arm. The character 【Null】 was there. But further up my arm, the characters continued.

【Muryoutaisu】

Great. That was my true EXP capacity.

When I was little, only the character for 【Null】 had surfaced, so no one else knew about the rest. I didn't even realize Muryoutaisu was a unit of measurement until my first year of middle school. The faintly emerging characters had finally become clear, prompting me to look it up out of curiosity.

Muryoutaisu. It meant ten sexdecillion, or $10^{68}$.

Written out in numbers, it looked like this:

100,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

That was a single Muryoutaisu.

When I first realized the truth, I practically shook. Men with EXP in the trillions were treated like national treasures. My capacity completely eclipsed that. I was a global asset. I figured I'd get VIP treatment higher than the American president and live an incredibly luxurious life.

But those expectations were quickly crushed.

Back in my first year of middle school, I had a crush. She had pale skin, long, beautiful dark-navy hair, and was a quiet girl who loved to read. Her name was Hamano Yura. We had been close enough to use first names in elementary school, but once middle school started and we were placed in different classes, we drifted apart.

I had come up with a foolish, naive delusion.

An autumn afternoon after school, inside a lonely library bathed in the setting sun. She, the library representative, would be quietly flipping pages in a room dyed madder red. I would abruptly enter, pick up some difficult, cool-looking classic piece of literature, and hand it to her at the counter. She would scan the barcode. Tatsuya-kun reads such difficult books, her heart would flutter. She'd open her mouth to speak, but her shy nature would hold the words back.

Handing the book over in silence, my fingers would briefly brush against hers. Just a slight touch usually transferred a tiny amount of EXP, but my overall pool was gargantuan. Even a 0.001% transfer would blast an unfathomable amount of EXP into her system. Receiving that much power, she'd completely fall head over heels. I love you, Tatsuya-kun! Please go out with me! It was a foolproof plan.

After night after night of fantasizing and running flawless mental simulations, I finally put the plan into action one autumn day.

I entered the library, found a complicated classic, and walked to the counter...

"...Oh. T-Tatsuya-kun. It's been a while. You read this kind of stuff?"

"Ah, yeah."

"Um... the return date is in two weeks. If... if you want, let me know what you think of it!"

"Sure."

She handed the book over with a bashful smile. Taking a leap of faith, I let my fingers brush against hers. That careless action was my ultimate mistake.

To a young girl who had barely awakened to puberty, an avalanche of astronomical EXP and pure ecstasy flooded her system. It wasn't just a simple crush-inducing flutter.

"...Ah... Aaaah... Ah..."

"Y-Yura-chan?"

Her eyes widened behind her long bangs, and her entire body began to tremble violently. A moment later—

"H-Hauuuuuuu! ♡♡♡♡♡♡♡♡ Nngh-kyuuuuuuuuuuu! ♡♡♡♡♡♡♡♡"

(Note: They were only touching fingertips.)

"Yura-chan?! YURA-CHAN!!"

Suddenly, hearts filled her eyes as she screamed through her shivers. Then, losing consciousness, she collapsed straight onto the floor.

Fortunately, the nurse's office was nearby, and the school nurse rushed over after hearing the scream. Faced with a situation I hadn't anticipated at all, I panicked, ran away, and hid behind a bookshelf. I should have helped her immediately, but back then, I froze. I stood there dazed, unable to comprehend the disaster I had caused, listening to the fading siren of the ambulance.

Yura-chan was gone the next day. The teacher claimed it was a sudden transfer, but I never learned the truth.

I was terrified. I thought she might have died, that I had killed her. But there was no way to check if she was alive. Searching social media only brought up strangers. If anyone found out Yura-chan ended up like that because of my EXP, what would happen to me? I was scared out of my mind.

From that day on, I hid my arm with an arm cover. I showed my pestering friends only the 【Null】 character to brush them off. And I managed to live my life avoiding any contact with women right up until today.

But today, the streak ended.

"I hope Sensei doesn't remember..."

I didn't know exactly how much EXP had transferred to her, but she definitely experienced enough ecstasy to pass out. Well, at least she had a pulse and was breathing normally, so it wasn't life-threatening.

"I wish this EXP would just drain away little by little."

Despite my wish, recent studies proved that EXP fully recovers after a night's rest. By tomorrow morning, I'd be right back to a full tank of Muryoutaisu.

"There's no way I can ever hook up with anyone like this..."

Skin-to-skin contact alone did that. If I actually went all the way, I'd undoubtedly kill the poor girl.

"Hope you get to fulfill your purpose someday, buddy."

I stared at my junk bobbing in the bathwater and sighed.

The next morning at school, Sakakibara immediately approached me.

"Mura! Did you hear the rumor about Sagaranche-sensei?"

Hearing her name made my heart skip a beat.

"Uh, no... what happened?"

"She's quitting her teaching job to return as a dungeon diver!"

"Huh?"

That was entirely unexpected. At the very least, it wasn't news about her dying, so I let out a breath of relief.

"That's incredibly sudden."

"Word is her level skyrocketed out of nowhere and she got insanely strong! Getting a massive power boost after retiring... man, that can only mean one thing. Sagaranche-sensei's been busy."

"Hey, don't get gross with your imagination."

There was only one way to level up after retiring from dungeon diving: absorbing EXP from a guy. And that method required intimate physical contact. To borrow Sensei's words from yesterday: intense sexual acts involving mucous membrane contact.

Despite warning Sakakibara, I couldn't help but think the same. Sensei was gorgeous and fit, so she must have been getting wild with plenty of guys to farm that much EXP. Otherwise, you couldn't get enough to make a comeback as a diver. Unless, of course, she touched someone with a completely broken amount of EXP.

"...Oh."

"What's wrong?"

"Ah, nothing."

Yeah, right. That massive chunk of EXP was almost certainly my fault. When she grabbed my arm and we fell onto the bed yesterday, a torrent of EXP must have transferred over.

Well, at least Sensei was alive and well. And considering she came to school right after, maybe fingertip contact wasn't as dangerous as I thought. Yura-chan had to be fine too.

Feeling a wave of relief, I went through the day until the final bell.

"Mura, you here?"

Right after homeroom ended, Sagara-sensei showed up at the classroom door. Since she was the hottest topic in school right now, every eye in the room locked onto me.

"Ah right. The apology letter from yesterday, right? I have it here."

I didn't actually have one, but I waved a random folded printout to play along. The class's intense gaze instantly dispersed. Getting weird rumors started would be a massive pain.

"Right, yes. Follow me to the nurse's office."

Whether she picked up on my quick thinking or not, Sensei matched my excuse and started walking.

"Hey Mura, what's this about an apology letter?" I asked quietly as we walked down the hall. "You're the talk of the school right now, Sensei. If a weird rumor links us, it's going to suck for me. It's just damage control. Now they'll just assume I messed up in class."

"...Sorry. That was careless of me."

"As long as you get it, we're good."

We kept our voices low until we reached the nurse's office.

"Get in."

"Got it."

I walked in as prompted and took a seat.

Click, snap.

"Click? Snap?"

A strange sound echoed, and the lights went out. The evening sun filtering through the window dyed the white room a deep, seductive orange.

"Um... Sensei?"

Turning toward the door, I saw Sensei slowly turn around from the light switch. The twilight illuminated her profile, casting an incredibly alluring, almost predatory vibe.

"Now, no one will come to save you."

"What do you mean by that?"

"Didn't I tell you every single health class? 'You boys are the ones who get devoured. Never let your guard down, even around those you trust.'"

"...Sensei?"

Sagara-sensei, usually the cool, dignified adult, was pinning me with a feverish, intense gaze.

"It's your fault for not listening in class, Mura. Oh, Mura, it's all your fault. You didn't pay attention to my lectures. Bad students need to be punished."

Her eyes were moist, and she muttered the words as if trying to convince herself.

"Sensei, my EXP is zero. I don't have anything to worry about."

"Heh... don't play dumb, Mura."

Slowly, she closed the distance.

"It couldn't be anyone else. Yesterday, you came to this office, I suddenly lost consciousness, and when I woke up, my level had exploded. I can only assume I received EXP from you."

"Sensei, you just fell asleep out of nowhere, so I went home. Maybe someone snuck in while you were out cold? Like, did something weird to you? Maybe you got EXP from them."

"I'm a virgin. And there was no physical discomfort when I woke up."

Did this gorgeous teacher really just drop that bombshell on a student?

"That 【Null】 on your arm... it's a fake tattoo sticker, isn't it? There are always guys who slap on fake thousands or millions to trick women. Granted, I've never heard of someone faking a low stat. But after yesterday's level up, it all clicks. Mura... you have a monstrous amount of EXP, don't you? And you're hiding it under that sticker."

"..."

She wasn't entirely wrong, but she missed the scale.

"Please, Mura. Do it with me."

"Do you hear yourself right now? You're talking about crossing the line with a student."

"I don't care if I get fired. I'm going back to dungeon diving. The crowd over there is rough anyway. A criminal record is basically just an accessory."

"That's not what I'm talking about. A serious, righteous person like you... is it really okay for you to do something that would traumatize a student? That's what I'm asking."

Appealing to her conscience worked surprisingly well. Sagara-sensei cast her gaze downward.

"...You're right. I was getting ahead of myself. I'm an idiot. I'm disqualified as a teacher."

She began to pour her heart out, bit by bit.

"Dungeons... they were my childhood dream. Standing on the front lines with my comrades, carving out a new world. That was my dream. Though it ended far too soon."

She gripped her left shoulder—the one missing its arm.

"Yesterday, when I woke up, my body was overflowing with vitality. I checked my level out of curiosity, and... I couldn't believe it. It shot up like crazy. My heart wouldn't stop racing. I realized if I could get that same amount of EXP just one more time, I could return to the front lines. Even with one arm, I could become strong enough to stand shoulder-to-shoulder with the top divers. I could stand on the front lines with the comrades who left me behind again."

Tears welled up, and she gently wiped her eyes.

"Mura, I'm so sorry. I did something pathetic. Trying to use a student for my own dream... it's unacceptable. Before being a teacher or a diver, I fail as a human being. Well... whatever the reason, the fact that my level went up doesn't change. I'll just have to work hard from the bottom up as a diver. Mura, you can go home now—"

"Sensei."

I cut her off and stood up, taking a step closer.

"You really are a great teacher. I respect you."

"Don't. Don't respect a failure of a teacher like me."

"I won't stop. And I don't want a teacher I respect to go out there and die."

If she was returning to dungeon diving, it was entirely because of me. And dungeon diving was a profession where death was a constant shadow.

"Sensei, I want you to be strong. Strong enough so you don't die easily. Strong enough to fight with one arm. I want you to survive and make it back to the surface."

"Mura, you..."

"Sensei. This is the last time. And you can't tell a single soul."

"M-Mura..."

As I closed the distance, her tear-filled eyes trembled. Sagara-sensei was a good teacher who genuinely cared for her students. I didn't want her carrying the guilt of forcing herself on one.

So, if someone was going to make a move, it had to be me.

"Sensei... try not to pass out from the pleasure, okay? Just hang in there."

"Mura... a..."

Before she could say another word, I pulled my hand out of my pocket and gently cupped her cheek.

Her entire body jolted violently.

"Ah... Mura... mnnnh! ♡♡♡ Muraaaaa! ♡♡♡ Ah, ah, ah... ♡♡ Nngh... I... I won't... I won't lose! ♡♡♡"

(Note: He was still just holding her cheek.)

"SENSEI! HANG IN THERE! RESIST IT, SENSEI!"

"I won't give inaaaaah! ♡♡♡ This is my limit line, sooooo! ♡♡♡ Nngh-kyuuuuuuuuuuu! ♡♡♡♡♡♡♡"

"S-SENSEI! YOU CAN DO IT! FIGHT IT, SENSEI!!"

The birth of the legendary dungeon diver known as the "One-Armed Berserker" was still a little ways off.